News

Comet Discovered at SkyCenter!

Wednesday, October 31, 2012

Daniel Stolte, University Communications

Dedicated only six months ago as the nation’s largest instrument of its kind devoted to public outreach and citizen science, the 32-inch Schulman Telescope at the Mt. Lemmon SkyCenter has shown that it can do more than offer awe-inspiring glimpses into the universe to those who travel up the mountain to participate in a public program about objects in the night sky.

Taking advantage of the telescope’s ability to be operated remotely via the Internet, Tomas Vorobjov, an amateur astronomer in Slovakia, discovered a previously unknown comet hurtling along its orbit around Jupiter.

“It is the first comet discovered by Mr. Vorobjov, as well as the first comet discovered by observers using the Schulman Telescope,” said Alan Strauss, director of the Mt. Lemmon SkyCenter, a public outreach station run by the University of Arizona’sdepartment of astronomy atop 9,157-foot Mt. Lemmon just north of Tucson.

Vorobjov had booked time on the Schulman Telescope to gather data for an asteroid search in one of the school campaigns organized by the International Astronomical Search Collaboration (or IASC, pronounced “Isaac”). The IASC is an education outreach program enabling high school and college students to make original discoveries of Main Belt asteroids – space rocks left over from the formation of the solar system.

The discovery came about through a partnership between IASC and the Sierra Stars Observing Network, or SSON, an organization that makes observation time on some of the world’s finest professional-grade instruments in observatories around the world available to paying customers.

Vorobjov, a software developer by day and an astronomer by night who directs the data reduction team of the IASC project, discovered the comet in data he acquired through his Near Earth Object work with IASC. The comet officially was recognized, designated and named on Oct. 18 through the International Astronomical Union's Minor Planet Center as “P/2012 T7 (Vorobjov).”

Vorobjov said he owes his discovery to a scheduling conflict.

“We originally scheduled our observations for Saturday (Oct. 14), but the SkyCenter telescope was used for local operations by visiting astronomers. Therefore, I had to move the jobs to Sunday. If the Schulman Telescope had been running for SSON on Saturday, the comet most likely would have been outside the field of view and I wouldn’t have found it.”

Vorobjov said he chose the Schulman Telescope because of the ease of operation, its outstanding optics and favorable location atop a tall mountain under the clear skies in Southern Arizona.

According to Vorobjov, about 100,000 asteroids are discovered each year, but only between 15 and 30 comets.

While similar in their origin as crumbs that did not make it into planets, asteroids and comets differ in composition and provenience. Asteroids are space rocks mostly confined to one of two distinct debris fields – one called the Main Belt and stretching between Mars and Jupiter and the other, called Kuiper Belt, fringing the solar system. Comets on the other hand come from the Oort Cloud, a vast accumulation of icy objects far, far away from the sun, beyond the orbit of the dwarf planet Pluto.

“Some comets come and go and come back,” Vorobjov explained. “But some only pass through the solar system and never come back.”

He explained that when a passing comet becomes trapped in Jupiter’s field of gravity, it joins the so-called Jupiter family. Measuring about 5 miles across, P/2012 T7 is one of those comets.

Vorobjov added that the discovery came out of a routine job he had submitted to SSON, which was to follow up on potentially unknown asteroids identified in a patch of sky that had not been observed for two months.

“Here is how you discover an asteroid: You take three images of the same field of sky about 30 minutes apart. Then you line up the stars in the images, which will appear fixed in position. An asteroid will appear as a dot moving through the field of stars.”

“I knew what asteroids look like and what comets look like,” Vorobjov said. “I noticed something to the right of what looked like an asteroid. It was very, very faint, you could barely see it. Asteroids look just like dots, but this one dot had a tail moving with it.”

Because SSON partners with observatories instead of owning the equipment, observers can make affordable observations on instruments otherwise not accessible to hobbyists or schools. Telescope time purchased through the network is affordable because SSON only brokers those times during which a telescope would sit idle because it is not used otherwise. SSON takes care of the operating the instruments and only charges for “shutter time,” i.e. actual observing time. SSON manages the data acquired through the network for SSON users.

“The data we get from the Schulman Telescope are extremely good quality,” Vorobjov said. “To observe a faint object like this comet with an instrument elsewhere, we’d have to spend about twice as much time and therefore more money.”

Richard Williams, founder and CEO of SSON, added: “The Schulman is an awesome telescope because it’s larger than many of the other instruments in our network, and that, along with it being on top of the mountain, allow you to observe objects that are one-half to one magnitude fainter of what can be observed with other instruments.”

The Schulman Telescope is operated by SkyCenter astrophotographer and astronomy educator Adam Block, who was recently honored for his contributions to astrophotography and bringing astronomy to the public.

SkyCenter director Strauss said, “This discovery is a significant event for us as we work in partnership with SSON to make the 32-inch Schulman Telescope available for remote use to astronomers, educators and citizen scientists worldwide.”

Soon, the Schulman Telescope will be joined in the SSON network by another UA-operated telescope, a 24-inch telescope also located at the SkyCenter that is currently being readied for remote operation.

Started in 2007, SSON is expanding into a global network, Williams said. “Our goal is all sky coverage, all the time, covering both hemispheres.”

Vorobjov said once he realized his discovery would have never happened without the scheduling hiccup, it made him wonder: “How many times have I missed comets in previous observations? Goes to show that in any kind of discovery or science there is a portion of luck. You’re not in charge of everything.”